Have you ever wondered what goes into making it possible to use the restroom at 30,000 feet (10,000 m)? [Jason Torchinsky] at the Autopian recently gave us an interesting look at the history of the loftiest of loos.

The first airline toilets were little more than buckets behind a curtain, but eventually the joys of indoor plumbing took to the skies. Several interim solutions like relief tubes that sent waste out into the wild blue yonder or simple chemical toilets that held waste like a flying porta-potty predated actual flush toilets, however. Then, in the 1980s, commercial aircraft started getting vacuum-driven toilets that reduce the amount of water needed, and thus the weight of the system.

These vacuum-assisted aircraft toilets have PTFE-lined bowls that are rinsed with blue cleaning fluid that helps everything flow down the drain when you flush. The waste and fluid goes into a central waste tank that is emptied into a “honey truck” while at the airport. While “blue ice” falling from the sky happens on occasion, it is rare that the waste tanks leak and drop frozen excrement from the sky, which is a lot better than when the lavatory was a funnel and tube.

The longest ever flight used a much simpler toilet, and given the aerospace industry’s love of 3D printing, maybe a 3D printed toilet is what’s coming to an airplane lavatory near you?